FICS and ICC both use a IRC style chat system were channels have numbers like 39 is politics on FICS and 97 is politics on ICC.
When playing, the board's action menu has an option to talk to opponent or last opponent.
Chat must be unlocked first which is simple. Just click the agree to EULA and accept the server policy on behavior which is basicaly keep it clean and nothing abusive.
To join a channel, click the Channels button in bottom right of Console. A list of channels to choose will appear and the user can tap on iOS or click on Mac to join one. The main view will now show only that channel and just type the users message to channel. To get back to console, channels button will now say console. Channel added to channels view will be removed from console to make less cluter in console. When remove channel is selected or another channel, the channel will be added back to console.
In channels view users will still see friend logged on and off notifications and if they get a private communication they will get a short message telling them. Type help notify in console to learn about friends lists. If the number is 221, to later remove it, type in console with command as the send prefix: -chan 221.
on ICC if joining, the last 10 tells in 20 minutes will be shown. On FICS no prior chat history will be shown. Type in console finger chlog, for how to get chat history on FICS.
Channels that chat more that I know of offhand are on FICS: shouts, 1 Help, 35 Music, 36 Science/math, 39 Politics, 40 Religion, 41 Current events, 50 General Chat. And on ICC: shouts, 1 Help, 2 Advanced Help, 34 Sports, 43 Chess Theory, 97 Politics, 103 Religion, 221 Tournament Requests, and 250 Lobby. Shouts are like channels but users type if they dont select it in list but from console, shout message. But first they must type under command, set shout 1, to listen to shouts. If chosen from list, this will be done for them. set shout 0, stops listening.
In the console one can chat on a channel by typing: tell # message. i.e. tell 39 hi. On FICS, first join the channel typing +chan 39 in console. This is not needed on ICC. To not have to type tell 39, click send prefix button and choose tell 39. Send prefixes will show for chat types currnetly displayed in console. To not have a send prefix before everything typed, re-select the command send prefix.